The Master of the Knights Templar's great seal was double-sided and showed the picture of The Dome of the Rock (some opinions are that the picture represents a circular dome of the Church of the Holy Sepulchre) on one side and the Order's symbol of two knights on one horse on the other side. There was also a smaller, single-sided seal, which showed the Dome of the Rock (or the circular dome of the Holy Sepulchre). Every Grand Master seal shares distinctive characteristics. In order to avoid misuse, special measures were taken regarding the seals. They were kept in a locked compartment which required three keys to open. The Grand Master himself kept one of these keys, and two of his high officials held the others. The forgery of the seals was a very difficult process because each seal was unique and hand made.

The officials of religious orders had their own seals to validate documents approved by the order. The seal was the equivalent of a modern day signature. Furthermore, in a time when the majority of people were illiterate, the seal was an acknowledgment of a document's authenticity. A seal was a declaration that the person or group whose seal was affixed validated the content of the document, even if they couldn't sign their names. The Templars, like any other individual or group, would have needed a seal whose imagery expressed something positive and fundamental about their organization.

According to a papal bull issued by Innocent IV in 1251, it was customary for successive provincial masters to use the same seal. When the province of Provence and certain parts of Spain were divided into two some changes were made. The master of Provence continued to use an Agnus Dei seal, but the seal of the Aragonese master William of Cardona, although round (29 mm. in diameter) and of black or dark-green wax, depicted a knight on horseback, carrying a lance and shield, on which was a cross bearing the legend: S. MINISTRI TEMPLI 1 ARAGON 7 CATALON ("Seal of the minister of the Temple in Aragon and Catalonia") . This form of seal was also used by later Aragonese provincial masters. Sigilum Xpisti ("Seal of Christ")

In heraldry, a Lamb of God (or paschal lamb, or agnus Dei) is a lamb passant proper, with a halo or charged with a cross gules, and the dexter forelimb reflexed over a cross staff from which a pennon of St. George (Argent a cross gules) is flotant. The seals of the Masters of the Temple in England: of Aimery de St Maur, 1200, Robert of Sandford, 1241, Richard of Hastings, 1160-85, and William de la More, 1304, showed the agnus Dei.

SIGILLVM TEMPLI The obverse of a seal used by William de la More, master, 1304, resembles the above text . The reverse, a small oval counter-seal, with beaded borders, shows on the right a couped bust of a bearded man wearing a cap. and have the legend:— TESTIS SVM AGNI ("I am a witness to the Lamb") William de la More, styled frater Willelmus de la More miliciae. The seal is called commune sigillum capituli. The seal symbolic of their vow of poverty, showing two knights riding on one horse appears only to have been used by the order in France; there is no example of its use in England.

Some of the seals of the English Templars were a semi-typical Pascal lamb bearing sometimes, not the flag of St George (or the cross), but the Beauseant, the battle banner of the order. The motto accompanying the seal reads TESTIS SUM AGNI, (not Agnus as is correct), being the lamb of God. The translation of the Latin word AGNI raises several areas of contention, however a similar word AGNITIO translates to "of the nature of the mind or wisdom".

The Templar Seal showing two knights (perhaps Hugues de Payens and Godfrey de Saint-Omer) on one horse. There are many interpretations of the symbolism of this seal.

* Contemporary legend held that the symbol represented the initial poverty of the order; that they could afford only a single horse for every two men. Still, the Rule of the Order from the outset permitted three horses and no more for each knight, as well as no Templars sharing the same horse.

* Several masters adopted this seal from the beginning of the order until at least 1298. It is known to have been in use since 1167. The Rule forbids two riders on the same beast.

The image of two knights on the horse was widely used:

* Matthew Paris in Chronica Majora ca 1250 * An English monk and chronicler from St. Albans in Historia Anglorum * At least as early as 1158 as the seal of the Grand Master of the Temple, Bertrand de Blanchefort. This is the earliest known seal for the Grand Master of the Temple forty years after the Order was formed. * Use of this symbol continued under subsequent Grand Masters for as long as the Order survived, however the seal went through more than one incarnation. The Reynaut de Vichiers, who was Master of the Temple from 1255-1259 depict same images, but it is obviously not the same seal.

Regarding the text of the seal differences can be clearly seen between the seals of the Grand Masters:

* Blanchefort's seal: SIGILLUM MILITUM obverse; CHRISTI DE TEMPLO reverse * Vichiers' seal: SIGILLUM MILITUM XPISTI. Although the phrase is written using the Latin alphabet, the first two letters of Christ's name are the Greek XP (Chi Rho) rather than the Latin CHR. The XP symbol's origin lies in the early roots of Christianity, but came into popular use after the Emperor Constantine had a vision of it and, according to legend, converted to Christianity in the early fourth century. From the time of Constantine, it became one of the most significant symbols of Christianity, surpassed only by the cross itself. Its early associations with the military make it the more apt of the two symbols for the Templars. In fact the Chi Rho can also be seen on the shields of the knights on de Vichiers' seal.

The eagle is an heraldic bird of the first order symbolising courage, determination, soaring toward great heights, power, grandeur. It is one of the most common charges on medieval heraldic shields, often denoting imperial sovereignty. The eagle is generally borne displayed; that is, upright, breast to the front, and legs, tail and wings expanded (commonly called a "spread eagle"). It signifies one eager or hot in the pursuit of an object much desired.

A Double Eagle and Eagle signifies a man of action, ever more occupied in high and weighty affairs, and one of lofty spirit, ingenious, speedy in apprehension and judicious in matters of ambiguity.

Emblematical of fortitude and magnanimity of mind. The Romans used the figure of an eagle for their ensign, and their example has been often followed. It is the Device of the Russian Empire, the Austrian Empire, the German Reichs, the United States of America and the Emperors of the French. In Blazon, when the talons, or claws and beak, are of a different tincture to the other part, it is said to be armed of such a colour. When the claws or talons are borne in arms, they should be turned towards the dexter side of the escutcheon, unless expressed to the contrary. An eagle displayed with two heads is commonly called a Spread Eagle, symbolical of the Eastern and Western Roman Empire. An eagle's leg erased at the thigh is termed á la quise.